Midi out port from keyboard to midi in schematic which connects to RX which connects to S2MIDI, which forwards it as a midi out. It also has options for parity, data bits, and stop bits. Parity is set to None. Data Bits is set to 8. Stop Bits is set to 1.

Oh I noticed that the Com port relating to arduino is set in device manager to have a 9600 Baud rate. Should I change this?

When I plugged in the midi interface that I bought it was already dysfunctional. I would play a note on the keyboard, and the computer would play a note only after I released a key. When I checked the midi commends that were being received by the purchased interface, it was giving a note off command when I pressed a key. I was never able to fix that. Well it doesn't seem like there is anything to try other then play with the baud rate. But thank you very much for all of you help. I appreciate it.

So I got this working and now modified the code to play a sound of the arduino, but I only get a quick beep and that's it.

If I hold a key down on my controller I don't get a continuos sound. I've simply changed the code to have a playsound routine that is played when a 'note on' command arrives. I assume midi doesn't keep sending a 'note on' command so it only makes it though that part of the if statement once, no matter how long I hold down the key.

I've tried a while loop with a statement to keep playing unless a 'note off' (128) is received with a serial.read inside the loop but then it never kick out off it

Suggestions? or am I missing something stupid because it was late at night?

I think I understand. separating each byte into a different variable? Does MIDI commands always come in 3 byte chunks? That would make it easer to break up the commands then having to use the if statement.

Yes, most MIDI commands are in 3 bytes.To be sure, just in case, read the status byte to know if it is in 3 bytes by type.I suggest you to look here to better understand how all the protocol works and the possibilities: http://www.blitter.com/~russtopia/MIDI/~jglatt/tech/midispec.htm